Method and apparatus for minimizing adverse effects of thermal expansion in a heat exchange reactor

Abstract

A heat exchange reactor including a housing, a plurality of tubes mounted in the housing and configured to carry a first fluid, and a baffle having a plurality of holes receiving the tubes. The baffle is configured to guide a second fluid provided within the housing to flow in a direction generally perpendicular to the tubes. The reactor includes various configurations for minimizing adverse effects of thermal expansion of the baffle and the tubes. The reactor is configured to minimize mechanical interference between the baffle and the tubes in both an operational state and a non-operational state, for example, by shaping the holes in the baffle to take into account thermal expansion. The reactor also includes a thermal insulator along a length of the tubes at a large temperature gradient zone within the reactor. The reactor further includes a heat transfer fin in contact with only one of the tubes.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to heat exchange reactors and methods of constructing heat exchange reactors.[0003] 2. Discussion of the Background[0004] Heat exchange reactors are often employed to carry out chemical reactions where significant quantities of heat must be added or removed from a first reacting fluid to a second heat transfer fluid, which may or may not be reacting. These heat exchange reactors often bear a strong resemblance to simple heat exchangers, but are often provided with additional features such as fixed beds of catalysts, specialized flowpath designs, exotic materials and the like. Heat exchange reactors are constructed in many forms, including plate-fin and tubular arrays.[0005] An example of a reaction conducted in heat exchange reactors is the steam reformation of hydrocarbon feedstocks to produce hydrogen-containing gas mixtures. In this process, a mixture of steam and hydrocarbon is passed through one fluid circuit ...

AI Technical Summary

Problems solved by technology

If free expansion is not allowed for in the configuration of the heat exchange reactor, then the unrealized strains result in thermal stresses.

The thermal stresses are particularly challenging in hydrocarbon steam reformers because the temperature gradients are generally very high.

The provision of features in tubular array heat exchange reactors presents formidable challenges due to the thermal gradients along the axis of the tubes.

These forces can cause premature structural failure of the reactor unless exceptionally strong tubes are employed, which is undesirable for several reasons, including an objectionable increase in the material usage in the construction of the reactor, as well as an attendant increase in volume and weight of the reactor.

Furthermore, the local stresses ca...

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